While you can't remove System Data entirely, it's possible to reduce the amount of storage it occupies. To accomplish this, you'll need to go through your Mac and manually delete unnecessary files ...

Apple’s privacy protections help, of course, but if you want to get proactive about removing your existing personal data from the internet, it’s never been easier to do so … ...

You browse on work computers, shop on public wifi, and leave traces across devices that don’t have Apple’s privacy protections. Data brokers are constantly harvesting these digital breadcrumbs.